Field of the Invention
The present invention relates to a film which is used in an image heating device, such as a fixing apparatus.
Description of the Related Art
An image-forming apparatus, such as an electrophotographic copying machine, electrophotographic printer, or the like, is provided with an image-forming unit which forms a toner image on a recording medium, and a fixing apparatus (image heating device) which carries out a heating process so as to fix the toner image onto the recording medium, for instance. The fixing apparatus forms a nip portion between a fixing rotating member and a pressing rotating member which rotate in pressurized contact with each other, whereby a recording medium on which an unfixed toner image has been formed by the image-forming unit is heated while being gripped and conveyed, thereby fixing the toner image onto the recording medium.
In a fixing apparatus of this kind, conventionally, a heat-resistant thin-film fixing film, for example, is used as a fixing rotating member or a pressurizing rotating member. Japanese Patent Application Publication No. 3-25481 discloses using a thermoplastic resin, such as polyether ether ketone (PEEK), polyether sulfone (PESU), polyether imide (PEI), or the like, as material for the fixing film. A thermoplastic resin can employ a method of manufacturing such as extrusion molding, and therefore has an advantage in that it can be produced inexpensively compared to a thermosetting resin.
However, if a thermoplastic resin is used as the material for a fixing film, then there is a concern that fatigue cracks may occur due to the insufficient bending resistance. On the other hand, if a thermoplastic film is used as the material of the fixing film, then there is a possibility of increase in the abrasion of the inner circumferential surface of the film due to insufficient abrasion resistance, and there are concerns about the occurrence of slipping of the fixing film due to the resistance caused by the abrasive dust.